Test farm news

Eric S. Raymond esr at thyrsus.com
Tue Jun 14 20:01:34 UTC 2016

Gary E. Miller <gem at rellim.com>:
> Yo Eric!
> On Tue, 14 Jun 2016 14:20:32 -0400
> "Eric S. Raymond" <esr at thyrsus.com> wrote:
> > Gary E. Miller <gem at rellim.com>:
> > > And none of this will do you any good until you wait another 7
> > > days.  If you had turned on logging last week you would have the
> > > data to look at now.  
> > 
> > There were good reasons I didn't.  Verifying a configuration that is
> > as simple and readily understandable as possible took priority.
> I'm still waiting for the good reason.  You can't ask the user to
> pick good offsets when he does not have the data for it.


Gary, I don't intend to ask the user to pick offsets at *all* at this
level.  That's an advanced topic.  At this point I don't expect to
cover it in 1.0.

I say this because I've watched enough Pi 3 output to know that at
steady state we're going to get well under 10ms offset and jitter
without fudging (I just picked one Pi at random and got 0.008 0.004).

That's good enough that we can *and should* ignore all the technical
complexities of fudging and log interpretation. We are *not addressing
time nuts* here.  We could do half an order of magnitude worse than
this and still be good enough for a beginner audience - in fact we'd
still be good enough to drive production WAN time service to RFC 5905
expectations or better.

You are very close to this stuff.  That is good because the domain
knowledge is extremely valuable.  But it can be bad because you get a
bit obsessive about problems that are challenging to *you* (fudging,
poor convergence time) and don't realize that from the point of view
of the newbies we're trying to bring gently on board with the HOWTO
you (and Hal) might as well be speaking ancient Sanskrit.

Please, would you at least *try* to have a bit more mercy on the
newbies?  And a bit more whole-systems perspective?  I know, I know,
that's my job - but have mercy on me.  When you go all narrow-focus
like this it increases the friction costs of my job and tends to drive
*me* crazy.

> > What's magic about 7 days, anyway?
> I am seeing what I assume to be sideral effects on a 24 hour cycle.
> Overlaid on that is a day or two of startup settling, and obvious
> room temperature effects.  I have trouble telling the apart with 4
> days or less data.

There, that's exactly what I mean by valuable domain knowledge.  One
of my to-dos is a white paper on NTP performance evaluation.  This
needs to be in it.
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>
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